Caption

Scanning electron microscope image of Strongylocentrotus drobachiensus [sea urchin] at the gastrula stage. Embryo was split open to reveal a nice cross-section through the outer epithelial layer and the blastocoel cavity. The fertilization envelope dissolves during swimming blastula stage; therefore, cilia and microvilli can be seen at the apical end of the epithelial layer. A few migrating primary mesenchyme cells can be seen within the blastocoel matrix.

Class Echinoidea

Superorder Echinacea

Order Echinoida

Strongylocentrotus drobachiensus

JEOL 35C SEM

Writer

Louisa Howard

Keywords

marine invertebrate, SEM, sea urchin, embryo